Process of modifying cellulosic textiles
with acrolein and aftertreating with
polyfunctional reactants



United States Patent 13 Claims. c1. 8-1164) This invention relates to the crease-proof finishing of cellulosic textiles, and in particular to the finishing of textile fabrics formed either completely or in major portion from cot-ton or regenerated cellulose fibers. In another aspect the present invent-ion relates to a novel finished cellulosic textile material having improved resistance to creasing, particularly when the material is wet.

The term textile as employed herein shall be understood to include textile materials of all kinds, including fibers, yarn, threads, knitted goods, and woven as well as non-woven fabrics. The term cellulosic textile material is intended to include textiles consisting entirely of natural or regenerated cellulose or mixtures of these cellulose types, as well as textiles in which a cellulosic material constitutes a major portion of the product and non-cellulosic fibers or filaments constitute the remainder or minor portion. The improvements to be derived by the method of the present invention are most pronounced on textile materials consisting entirely of cellulosic fibers, for example cotton, the rayons, or mixed cotton and rayon goods.

It is well known that cellulosic textiles, especially cotton fabrics, when treated with the typical finishing synthetic resin precondensates for example the methylol ureas and urea derivatives as well as melamine which penetrate the cellulose fibers and then by heating in the presence of a catalyst are converted to insoluble resins by polycondensation in and on the fiber, acquire the property of recovering in a relatively short time a major portion of any deformation produced in the fabric as a result of wrinkling or creasing in dry condition. On the other hand, wrinkles and creases produced While the fabric is wet, for example those formed during normal laundering, do not disappear to any appreciable extent with the passage of time. Thus, fabrics which have been treated with the aforementioned typical resin precondensates may be regarded as crease or wrinkle resistant only insofar as the wrinkling on creasing isbrought about while the fabric is dry. By reason of their poor wet crease resistance they do not possess satisfactory washand-wear properties.

Accordingly, it is a primary object of the present in vent-ion to provide a method for imparting completely satisfactory wash-and-wear properties to a cellulosic textile material.

It is a further object of the present invention to provide a method for very substantially improving-the wet crease resistance of a cellulosic textile material while also improving its dry crease resistance.

It is a still further object of the present invention, among others, to provide a novel finished cellulosic textile material which is characterized not only by an acceptable dry crease resistance but also by a very substantially improved resistance to wrinkling or creasing while the textile is wet.

We have found that a very substantial improvement in the wash-and-wear properties of a cellulosic textile material can be achieved when acrolein is polymerized in and on the cellulosic textile and a polyfunctional reactant, for example an aliphatic, aromatic or heterocyclic 3,254,941 Patented June 7, 1966 alcohol,-amide or amine, is then condensed with the acrolein polymer.

While the mechanism whereby the improvement in crease resisting properties of the textile is achieved is not yet fully understood, it is believed that the acrolein undergoing polymerization in and on the fibers of the cellulosic fabric also forms some chemical bonds with the cellulose polymer. The thus polymerized acrolein contains appreciable free aldehyde groups, and possibly also occasional carbon-to-carbon unsaturations, which are capable of forming reaction products, that is condensation products with the alcohols, amides or amines. By reason of their polyfunctionality, the reactants are capable of reacting with the aforementioned aldehyde or unsaturated groups in more than one acrolein polymer molecule thereby serving as a cross-linking bridge in the poly acrolein, which would seem to account for the very substantial increase in wet crease resistance as demonstrated hereinafter. While polyacrolein is of course capable of engaging in condensation reactions with monofunctional alcohols, amides or amines, no such positive direct crosslinking within the polyacrolein is likely to occur with a monofunctional condensation reactant. Accordingly, the present invention contemplates only the use of polyfunctional reactants of the aforementioned types, with polyfunctional alcohols and amides being preferred.

Polymerization of the acrolein is accomplished in the presence of one of the well known alkaline catalysts in the presence of water or other media which will enable the catalyst to become manifest. For example, the catalyst may be applied by immersing the fabric in a dilute aqueous solution of the catalyst or by spraying the fabric with the catalyst solution.

Suitable catalysts include the alkali metal carbonates or hydroxides, lime, lead hydroxide, ammonia, the amines, etc. The weak alkalis potassium or sodium carbonate areperhaps the most convenient catalysts and will generally be employed for the polymerization, and will be applied 'to the fabric from about 1 to 2% aqueous solution. In accordance with preferred embodiments of the present method the catalyst is imparted to the textile by dipping the latter in a dilute catalyst solution of the catalyst or by spraying the catalyst solution onto the textile to a wet pick-up of about 70-90%. Following catalyst impregnation the textile is contacted with acrolein either by spraying an aqueous solution of acrolein onto the textile, by dipping thetextile in an aqueous acrolein solution or by contacting the textile with acrolein in the gas phase in a confined zone. The moisture content of the textile material to be contacted with acrolein gas is particularly critical; with decreasing water content of the fabric, the dry crease recovery angles increase. Application of acrolein gas is preferably carried out at a temperature of about 20-70 C., with the goods being maintained in contact with the gas for periods ranging up to about 10 minutes. When contacting is by spraying or immersion in an aqueous solution of acrolein, this treatment is carried out at temperatures between about 15 and 40 C. and the textile is exposed to the aqueous acrolein solution for periods up to about 30 minutes. When application of acrolein is from an aqueous solution, the impregnating solution will generally contain up to about 50% by weight acrolein. In either gas or liquid application about 0.5 to about 10% by weight acrolein is imparted to the textile. The aforementioned exposure times for gas phase and aqueous phase application are generally for minimum times of at least one minute, and during this exposure polymerization of the acrolein readily occurs at the aforementioned temperatures in the presence of the catalyst. As noted above it is believed that some chemical bonding between'the acrolein' or acrolein polymer and the cellulose occurs.

Following application and polymerization of the acrolein the textile is desirably although not necessarily washed with water to remove excess catalyst prior to subsequent treatment in accordance herewith. Washing is not essential since an acid catalyst is employed in the condensation reaction, which acid catalyst will readily neutralize any excess acrolein polymerization catalyst which may remain on the unwashed textile.

The textile bearing the polymerized acrolein is then treated with an aqueous solution, dispersion or emulsion containing one or more of the aforementioned polyfunctional reactants. This treament may be by spraying of the acrolein-treated textile with the aqueous medium containing the polyfunctional reactant, in which case the textile is substantially completely saturated with the aqueous medium, but preferably the textile is immersed in a bath containing the polyfunctional reactants in amounts up to about 2.5% by weight of the bath, preferably between about 5 and 20% by weight. This bath or the spraying solution, dispersion or emulsion also contains the usual acid condensation catalyst, which term as employed herein and in the appended claims is intended to include also the potentially acid catalyst types. Typical catalysts employed to facilitate condensation of the alcohol, amide or amine with the acrolein polymer on the textile include oxalic or citric acids, zinc chloride, magnesium chloride, zinc fluoroborate, magnesium perchlorate, diammonium phosphate, etc. One or more of these catalysts is present in the polyfunctional reactant bath or Spraying medium to the extent of about 0.5-3% by weight thereof.

Following treatment with the polyfunctional reactant, the textile is dried at elevated temperatures and condensation or curing is effected by subjecting the textile to temperatures within the range of about 70 to 150 C. for periods ranging from about 3 to 30 minutes. In this connection the textile may be removed from the polyfunctional reactant impregnating bath and immediately subjected to the aforementioned condensation or curing temperatures, or the treated textile may be dried at a substantially lower temperature, even at room temperature, and condensation effected by subsequent higher temperature treatment within the aforementioned range.

The polyfunctional reactants which are essentials to production of the improved crease resistant finished cellulosic textile of the present invention include the polyfunctional alcohols which are capable of forming acetals and diacetals. Particularly suitable are alcohols containing four to six functionl groups, for example, pentaerythritol and mannitol. Other polyfunctional alcohols include the glycols, particularly trimethylene glycol, glycerine, vinyl alcohol polymers, etc.

Suitable polyfunctional amides in accordance with the present invention include urea and its derivatives, particularly monoethyl urea, ethylene urea and the methylol ureas. The acrylamides, heterocyclic aromatic acid amides, e.g., melamine aliphatic acid amides and diamides may also be employed. Preferred polyfunctional amines include hydrazine and aliphatic diamines such as tetramet-hylenediamine and hexamethylened-iamine, for example. It is also possible to employ mixtures of polyfunc tional alcohols and amides or amines, and in this connection particularly useful combinations include the four to six functional alcohols and urea or the urea derivatives.

It is to be understood that the above set forth typical polyfunctional amides, amines and alcohols are only specific members of these broad classes of polyfunctional reactants which may be employed in accordance with the present invention. To enumerate all of the polyfunctional alcohols, amides and amines which will condense and cross-link with polyacrolein would be a virtually impossible task. Accordingly it is to be understood that typical representative members only are set forth herein from which one skilled in the art may readily be led to others of these classes.

The present method is particularly applicable to cellulosic textile materials in web form, and the acrolein and polyfunctional reactants are easily applied to a textile web from aqueous media with conventional textile finishing equipment. In the case of application of acrolein gas to the web slight modifications of existing equipment will of course. be required.

It has further been found that the present method is also eminently well suited to the finishing of fine cotton or regenerated cellulose fabrics which have been rendered stiff and/or transparent by treatment with concentrated sulphuric acid, cuprammonium or sodium zincate-cellulose solutions, and is also applicable to the finishing of fine fabrics constructed of relatively highly twisted yarns such as voille and marquisette. The present invention thus provides a method for achieving very substantially improved resistance to wet creasing in these stiff and/or transparent fabrics without any notable reduction in the strength of the fibers thereof.

The present invention will now be described in further detail by reference to the following examples which set forth representative polyfunctional reactant types which may be employed. The invention is of course not limted to the specific reactants mentioned in the examples.

Example 1 A coton fabric (125 grams per square meter) was impregnated with a 1% aqueous potassium carbonate solution and squeezed off to about 80% wet pick-up. The fabric'was then subjected in a confined space to acrolein gas at about C. for 2 /2 minutes. The fabric was removed from the acrolein atmosphere and washed with water, .after which it was impregnated by immersion in an aqueous solution containing 10% by weight pentaerythritol and 4% by weight zinc chloride, preliminarily dried and then finally sub-jected to a temperature of 125 C. for a period of 10 minutes to effect condensation or curing.

A cutting of the thus treated fabric was thereupon washed with a standard soap solution containing tripolyphosphate and sodium carbonate in a washing machine at C., rinsed and hung up in air for evaluation of the wet crease pattern imparted during washing. This evaluation was by visual inspection and comparison with five standard samples ranging from very good to very poor crease patterns, bearing the marks 5 to 1 respectively. Thus, the standard sample with very good resistance to creasing bears the number 5 and the sample with very poor resistance to creasing, i.e., very severe wrinkles or creases, bears the number 1. Following this inspection a plurality of pieces were cut from the washed fabric and from the untreated cotton and the wet and dry crease angles of the washed fabric as Well as the starting material were measured, with the followinga verage results:

Creasing angles were determined for the wet and dry fabric samples as follows: Strips of the fabric 3 x 5 cm.

Weft Dry Weft Wet Visual creasing creasing Crease angle angle Pattern Evaluation Starting Material 33 75 Treated Material 90 145 4.

Example 3 The cotton fabric of Example 1 was soaked for one hour in a 2% aqueous potassium carbonate solution and then squeezed to a wet pick-up of about 80%. The wet fabric was exposed to acrolein gas at about 50 C. for 2.5 minutes. Thereupon the fabric was impregnated by immersion in an aqueous solution containing mannitol and 1.5% oxalic acid, preliminarily dried and then heated to 120 C. for 10 minutes. The fabric was washed as in Example 1 and exhibited the following improved properties:

Welt Dry Weft Wet Visual creasing creasing Crease angle angle Pattern Evaluation Starting Material 33 75 Treated Material 95 145 4. 5

Example 4 A cotton fabric weighing 125 grams per square meter was impregnated with a 2% aqueous solution of potassium carbonate and squeezed off to about 80% wet pickup. The fabric was then slightly predried on a tentering frame, and while still in moist condition it was sprayed beyond the point of saturation with a 30% aqueous solution of acrolein at a temperature of about -20" C. and allowed to remain on the frame following spraying for about 15 minutes. The fabric was then rinsed, treated with the aqueous solution of pentaerythritol and zinc chloride, dried and heated as in Example 1. It was then subjected to the standard washing of Example I, hung to dry and crease angle determinations made. The fabric thus treated showed a very substantially increased dry and wet crease resistance and the crease pattern following washing was very good as compared with the starting material.

Example 5 A cotton fabric was treated with acrolein gas and washed with water in accordance with Example 1. It was then impregnated with an aqueous solution containing 5% pentaerythritol, 5% monoethyl urea and 1% oxalic acid, preliminarily dried and heat-treated at about 110 C. for 10 minutes. The fabric was then subjected to the standard washing described in Example 1 land crease angles in both wet and dry condition were determined. The dry and wet crease resistance were very substantially improved and the fabric had a very good crease pattern as compared with the starting material.

Example 6 A cotton fabric weighing 125 grams per square meter was impregnated with a 2% aqueous potassium carbonnate solution to a wet pick-up of about 80%, and predried to about 7% moisture. The fabric was-thensubjected in a closed vessel to acrolein gas at about 60 C.

for 7 minutes, removed from the vessel, Washed with water and then immersed in an aqueous solution containing 10% by weight ethylene urea and 1% by weight zinc chloride. The fabric was then preliminarily dried and finally cured at 120 C. for about 10 minutes. The thus treated fabric was washed as set forth in Example 1 and tests were conducted with the following results:

Weft Dry Weft Wet Visual creasing creasing Crease angle angle Pattern Evaluation Starting Material. 33 75 Treated Material 150 4. 5

Example 7 Weft Dry Weft Wet Visual creasing creasing Crease angle angle Pattern Evaluation Starging Material 33 75 Treated Material 145 4 Example 8 The cotton fabric of Example 6 was impregnated with a 2% aqueous solution of potassium carbonate, squeezed off to about 80% and predried to about 7% moisture. The fabric was then subjected to acrolein gas at a temperature of about 50 C. for 2.5 minutes washed with water, immersed in a aqueous solution containing'10% by weight glycerine and 1% by Weight zinc fiuoroborate and squeezed off to about 80%. The thus treated fabric was preliminarily dried and finally cured at about C. for 10 minutes. The fabric was washed and crease angles determined as in Example 1 with the following results:

The cotton fabric of Example 6 was impregnated with 2% aqueous solution of triethanolamine, squeezed off to about 80% and pre-dried. The fabric was then subjected to acrolein gas at a temperature of about 50 C. for 5 minutes, washed with water, immersed in an aqueous solution containing 5% by weight hydrazine hydrate and 1% by weight zinc nitrate and squeezed offto about 80%. The thus treated fabric was preliminarily dried at 60 C. and finally cured at about 120 C. for 10 minutes. After washing the fabric exhibited dry creasing angles and wet creasing angles in the weft of more than 100.

Example 10 The cotton fabric of Example 6 was impregnated with a 2% aqueous solution of trimethylamine, squeezed off to about 80% and pre-dried. The fabric was then subjected to acrolein gas of about 50 C. for minutes, washed with water, immersed in an aqueous solution containing by weight hexamethylenediamine and 1% by weight zinc fluoroborate and squeezed off to about 80%. The thus treated fabric was preliminarily dried at 60 C. and finally cured at about 120 C. for 10 minutes. After washing the fabric exhibited an excellent dry and wet crease resistance.

We claim:

1. Method for improving the wet crease resistance of a cellulosic textile, which comprises contacting said textile with acrolein in amount sufficient to impart thereto about 0.5 to about 10% acrolein, polymerizing the acrolein so imparted to said textile in and on the same in the presence of an alkaline catalyst for said polymerization in contact with said textile, impregnating the textile having the acrolein polymerized therein and thereon with a polyfunctional reactant capable of reacting at its functional sites with free aldehyde groups in the acrolein polymer selected from the group consisting of polyfunctional alcohols, amines and amides, and condensing the polyfunctional reactant with the acrolein polymer in the presence of an acid condensation catalyst.

2. Method for improving the wet crease resistance of a cellulosic textile, which comprises imparting to said textile a catalytic amount of an alkaline catalyst for the polymerization of acrolein, contacting said textile with acrolein gas at a temperature between about and 70 C. for a time sufficient to impart between about 0.5 and 10% by weight acrolein to said textile, whereby at said temperature and in the presence of said catalyst polymerization of the acrolein occurs in and on the textile, contacting the so treated textile with an aqueous medium containing about 5 to 25% by weight of a polyfunctional alcohol containing 4 to 6 hydroxyl groups, and subsequently heating the textile in the presence of an acid condensation catalyst at a temperature between about 70 and 150 C. forperiods up to about 30 minutes to effect condensation of the polyfunctional alcohol with the acrolein polymer.

3. Method for improving the Wet crease resistance of a cellulosic textile, which comprises contacting said textile with acrolein in amounts sufficient to impart about 0.5 to about 10% by weight acrolein thereto, polymerizing the acrolein in and on said textile in the presence of an alkaline polymerization catalyst at a temperature between about 15 and 70 C., subsequently impregnating the thus treated textile with a polyfunctional reactant of the group consisting of polyfunctional alcohols, amides and amines and condensing said reactant with the acrolein polymers in the presence of an acid condensation catalyst at temperatures between about 70 and 150 C.

4. Method as set forth in claim 3 wherein the polyfunctional reactant is imparted to the acrolein-treated textile from aqueous media containing the polyfunctional reactant in amounts of about 5 to 25% by weight.

5. Method for improving the wet crease resistance of a cellulosic textile, which comprises contacting said textile with acrolein gas at a temperature between about 15 and 7 0 C. in the presence of an alkaline polymerization catalyst for a period sufficient to impart about 0.5 to 10% by weight acrolein to said textile, whereby said acrolein is polymerized in and on said textile, subsequently impregnating the thus treated textile with a polyfunctional reactant of the group consisting of polyfunctional alcohols, amides -and amines and condensing said reactant with the acrolein polymer in the presence of an acid condensation catalyst at temperatures ranging from about 70 to about 150 C.

6. Method as set forth in claim 5 wherein prior to contact with the acrolein gas the textile is impregnated with the alkaline polymerization catalyst dispersed in aqueous media.

7. Method for improving the wet crease resistance of a cellulosic textile, which comprises contacting said textile with an aqueous solution of acrolein for a period up to about 30 minutes at temperatures ranging from about 15 to about 40 C. in the presence of an alkaline polymerization catalyst in contact with the textile, whereby about 0.5 to 10% acrolein by Weight of the textile is polymerized therein and thereon, subsequently impregnating the thus treated textile with a polyfunctional reactant of the group consisting of polyfunctional alcohols, amides and amines and condensing said reactant With the acrolein polymer in the presence of an aicd condensation catalyst at temperatures above about 70 C.

8. Method for improving the wet crease resistance of a cellulosic textile, which comprises contacting said textile with acrolein to impart about 0.5 to 10% by weight acrolein thereto and polymerizing the acrolein in and on said textile in the presence of an alkaline polymerization catalyst at about 15 to 70 C., subsequently impregnating the thus treated textile with a polyfunctional alcohol and heating the textile to between 70 and C. for in excess of about three minutes in the presence of an acid condensation catalyst to condense the alcohol with the acrolein polymer.

9. Method as set forth in claim 8 wherein the polyfunctional alcohol contains 4 to 6 functional groups.

10. Method as set forth in claim 9 wherein the alcohol is pentaerythritol.

11. Method for improving the wet crease resistance of a cellulosic textile, which comprises contacting said textile with acrolein to impart about 0.5 to 10% by weight acrolein thereto and polymerizing the acrolein in and on said textile in the presence ofan alkaline polymerization catalyst at about 15 to 70 C., subsequently impregnating the thus treated textile with a polyfunctional amide and heating the textile to between 70 and 150 C. for in excess of about three minutes in the presence of an acid condensation catalyst to condense the amide with the acrolein polymer.

12. Method as set forth in claim 11 wherein the polyfunctional amide is a urea derivative.

13. A cellulosic textile o1 improved resistance to wet creasing comprising a cellulosic textile base material.

having deposited therein and thereon polymerized acrolein in amounts of about 0.5 to about 10% by weight of the textile material said deposited acrolein polymer being cross-linked through in situ reaction with a polyfunctional reactant of the group consisting of polyfunctional alcohols, amides and amines.

References Cited by the Examiner UNITED STATES PATENTS 2,415,039 1/1947 Rust 8116.4 X 2,600,780 6/1952 Kohler 8116.3 X

FOREIGN PATENTS 783,123 9/1957 Great Britain.

OTHER REFERENCES Chance et al., Textile Research Journal, vol. 30 #4, April 1960, pp. 305-311.

J. TRAVIS BROWN, Acting Primary Examiner.

JULIAN S. LEVITT, Examiner.

J. CANNON, Assistant Examiner. 

1. METHOD FOR IMPROVING THE WET CREASE RESISTANCE OF A CELLULOSIC TEXTILE, WHICH COMPRISES CONTACTING SAID TEXTILE WITH ACROLEIN IN AMOUNT SUFFICIENT TO IMPART THERETO ABOUT 0.5 TO ABOUT 10% ACROLEIN, POLYMERIZING THE ACROLEIN SO IMPARTED TO SAID TEXTILE IN AND ON THE SAME IN THE PRESENCE OF AN ALKALINE CATALYST FOR SAID POLYMERIZATION IN CONTACT WITH SAID TEXTILE, IMPREGNATING THE TEXTILE HAVING THE ACROLEIN POLYMERIZED THEREIN AND THEREON WITH A POLYFUNCTIONAL REACTANT CAPABLE OF REACTING AT ITS FUNCTIONAL SITES WITH FREE ALDEHYDE GROUPS, IN THE ACROLEIN POLYMER SELECTED FROM THE GROUP CONSISTING OF POLYFUNCTIONAL ALCOHOLS, AMINES AND AMIDES, AND CONDENSING THE POLYFUNCTIONAL REACTANT WITH THE ACROLEIN POLYMER IN THE PRESENCE OF AN ACID CONDENSATION CATALYST. 